The present invention relates to a method for controlling an air conditioning system of a type wherein the rotational speed of a compressor provided therein is changed in accordance with the load of the air conditioning system.
An air conditioning system is a system for maintaining various aspects of the air within a certain space. The load of the air conditioning system or the air conditioning load includes a heating load, i.e., amount of heat to be given to the air within a unit time, or a cooling load, i.e., amount of heat to be removed from the air within a unit time. The load of the air conditioning system also includes a humidity regulating load, i.e., amount of moisture to be given to or removed from the air within a unit time. However, because the temperature is a greater factor, the air conditioning load can be roughly estimated from the deviation of the actual temperature with reference to the temperature set value.
On the other hand, the cooling or heating power or effect of the air conditioning system can be varied over a wide range by varying the rotational speed of a compressor provided in the air conditioning system.
It will therefore be appreciated that varying the compressor speed in accordance with the air conditioning load will improve the efficiency of the air conditioning system and reduce energy consumption.
A conventional control system for varying the compressor speed in accordance with the air conditioning load includes linear circuits wherein an analog (continuous or nondiscrete) signal is used for indicating the difference between the detected temperature and the reference temperature and as a basis for determining the frequency of the AC current supplied to the compressor motor. As a result, the circuitry of the conventional system is complicated.